Various mixer valves for hot and cold water incorporate a mixer unit including two overlapping disks or plates in a ceramic material or the like, one disk or plate being fixed and the other movable on the fixed one. The fixed disk has two water inlet holes which are joined to two separate pipes for hot and cold water and an outlet hole which coincides with the mouth of the water delivery tap. The movable disk has a mixing chamber designed to selectively join one, the other or both the water inlet holes with the outlet one.
However, it has been found that the passing of the water from the inlet holes of the fixed disk to the mixing chamber of the movable disk and then to the outlet and delivery hole results in the structure being noisy as well as leading to cavitations and load loses which negatively influence the effective capacity of the valve. So, in order to ensure a standard capacity it is not possible to reduce the span of the passages further than a certain limit which also prevents the reduction in the size of the disks or plates and therefore of the valve as would be expected. On the other hand, the reduction of the span could be the cause of a noise increase. Thus it is necessary to continue the research in order to find a compromise in said mixer valve which permits the noisyness to be maintained and ensures a capacity within the forseen standard limits, and which allows for a reduction in the size of the overlapping disks or plates and consequently of the valves.
Attempts which have so far been made have obtained worthy results, which can still be improved upon, as far as noise reduction is concerned but often resulting in a loss of capacity.
A method for solving the problem has been proposed in patent IT-A-1207763, by the same applicant, relative to a mixer valve incorporating a movable plate, the mixing chamber of which has an antinoise element, made from a metallic net, with two parts which are perpendicular to each other and form two permeable barriers designed to be traversed by the flow of water from the inlet holes to the outlet hole through the mixing chamber.
Even though said barriers are permeable and suitable for the reduction in noise of the flow, they tend to limit the capacity and therefore do not obtain the forseen results.